Can I do grad studies in computational physics if my BSc is in chemistry?

Just wondering how different the two really are. I'm interested in developing functionals and was wondering if the two are really distinguishable. On an added note, by the time I graduate, I will have had two research terms in computational chemistry. One applications, and the other developing functionals. So, may computational physics supervisors consider me as a grad student?

I don't know what "developing functionals" is (I do construct functionals to extract data from probability distributions, but I have the feeling that is not what you mean) and I don't know the "grad school" system in the US. But I can tell you that our "Computational Biophysics" group has quite a few PhD students and post-docs who did their Masters or PhD in biology, chemistry, or engineering (although to be fair I must add that part of the reason for this is the lack of adequate physics applicants). There is a large overlap region between chemistry and physics (think soft condensed matter physics and physical chemistry), so I think that a lot of computational chemistry is sufficiently close to some computational physics to make a transition quite easy. But please keep in mind that this statement is merely based on knowing a bit about physics, chemistry, and computing - I don't know the US university administrations at all.